Art of converting oils



Sept. 8, 1931. N. E. Loomis ET AL ART oF CONVEHTING oILs Filed May '7. 1927 Patented Sept. 1,931 l l UNITED/fermes PATENT OFFICE NATHANrEr. :sg/Doom, or wnsTrmLD, AND' LoUIs Bimenes, or nosELLE, Naw

JERSEY, .A

or DELAWARE ssIeNoas To STANDARD on. DEVELOPMENT comm, A coaronATIon ABT F CONVEBTING OILS vApplication led Hay 7, 1927. Serial No. 189,478.

This invention relates to a method for co n verting hydrocarbon oils into lower bollin oils by heating such oils with alumrmum chloride and more particularly by heating such oils incontact with aluminum chloride at higher temperatures than are posslble under normal atmospheric pressures. Thls 1s a continuation in part of our prlor co-pending application, Serial No. 532,839, iled Janio ua so, 1922.

is invention has for its objects, among others, an increase in the amount of low b011- ing oils recoverable, an improvement 1n efficlency of the aluminumchloride catalyst l5 and anI increased output from apparatus of any given size. l' tages will be apparent from the specification.

The drawing which accompanles thls application shows a vertical section off appa- !0 ratus suitable for' carrying the invention Into effect. The num'eral 10 designates a suitable still, preferably having a dished bottom and m-ounted in a suitable urnace setting 11. In the still is mounted a stirrer 12, which may l5 suitably be of rectangular form. The stirrer is secured to the rotatable shaft 13, which passes through a stuffing box andjournal 14:v

at one endand at' the other end is mounted in a thrust bearing in a spider 15 secured to the l0 bottom of the still. l:Dragging scrapers 16 are pivotally secured to the bottom reach of the stirrer 12, these Scrapers covering substantially the entire bottom of the still on each rotation of the stirrer, in substantiall the man- 5 ner shown in the copending a p ication of on;7 of us Serial Nlo. 183,285 li ed April 13, 19 i At the top of the still there is provideda suitable covered man-hole 17. In the bottom D of the still is a discharge openin 18, which is normally closed by a valve 19 ofg the poppet type. Below the opening 18 is a discharge chamber of substantially cylindrical sha e,

to the wall of which is secured a guide 21 tor 5 the operatingstem 22 of valve 19. The valve stem 22 is preferably'formed with a rack,

as illustrated, and is operated bymeans of a gear '23 mounted upon the shaft 24 which extends to the exterior of the fur- D nace setting and is provided with a suitable Other objects and advan- 'is provide ply i ev the throug pipe 30, opening into the upper porl tion of t edischarge chamber. O11 passing out of the chamber through the ipe 30 may be discharged into the -still vt rough the valved pipe 31 or may be introduced into the inlet pipe 28 through the ipe 32.

\ Vapors formed in the st11l pass 'out through(Y the vapor line 33 into the down-flow vertical tubular condenser y34. From this the cooled .gases and condensed liquids discha through pipe 35 into the receiver 36.-'-T e gases separatin in the receiver pass out through gas disc arge line 37 provided with l a suitable adjustable pressure release valve 38. A gas bypass 39 (provided with a valve aroun the pressure control valve 38. Condensed liquids in the drum 36 maybe discharged through valved pipe 41. We have found that in carrying out the distillation of oils in contact with a catalyst containing aluminum chloride, the eiciency of the catalyst can be materially increased by maintaining the oils in contact with the catalyst at higher temperatures than had been previously employed. These .higher temperatures referred to are above the normal boiling point of the oilunder oing con'version and may even be-as high as 00 or 800 F. although temperatures between 650 and 750. F. are ordinarily employed. Operation under these conditions is possible as we havedis` l covered only by the application of considerable pressure to the materials undergoingdecomposition. This' pressure must be greater than the vapor, pressure of the oil to A be converted and less than the vapor pressure of the desiredproduct at the temperature of conversion.

While our invention comprehends any application of pressure under the conditions referred to, our preferred method comprises the application of pressure to the method of distilliug oils in contact with aluminum chloride outlined in application of one of us- Serial No. 183,285, iiled April 13, 1927. As specifically recited therein, .this application comprehends a method of distilling oils in which the oil is held at a temperature at which a certain composition of distillate is pro.

duced. This composition of distillate is not pure gasoline, but such'a ratio of gasoline, kerosene, and charge stock as will yield a maximum financial return when taking into account all .of the factors connected wit 1 the operation of the process. When ope ating under the process referred to, aluminum chloride or a catalyst containing the same,

is supplied to the still in a uniform and sustained 'manner at a rate proportional to the rate .at which distillate is evolved, .4 while oil is supplied to the stillat a rate suficiently to maintain the volume of still contents substantially constant.v

In the presentprocess the gage pressure Yis preferably 100 to 300 lbs. per square inch.

. Thus with a charge of gas oil at a temperature -of about 700-F., an operating pressure `of 30.

position of distillate evolved and pressures` in the neighborhood of 250# gauge may ordinarily e required. Itwill, of course, be understood that the particular pressures mentioned should be s uicient to maintain the de- Sired composition of evolved distillate, that any pressures necessary to this end, may be maintained and that the particular pressures mentioned are illustrative and not by way of limitation. We have, moreover, discovered that by the application of pressure'in this manner, the rate at which the still can be operated is# considerably -increased. The

Itendency to the loss of aluminum chloride `or aluminum chloride hydrocarbon compounds.

and charge stock from th'e still -as a result of a mechanical transport is considerably diminished and the daily turnover from a still of a definite size can be considerably increased.

Having described our invention, we will proceed to Adescribe a method of operating the same without limitation, however, as to.

panics the specilication,'the still 10 is charged about two-thirds full of the hydrocarbon to be decomposed. Heat is then applied by means of the burner shown. During the first period of heating, the by-pass valve 40 is preferably left open to permit the escape of air from thestill. gins to be evolved, this valve is closed entirely and the regulating valve 38 is set at a pressure of 100# gauge. The liquid is then carried up' to the desired temperature of operation which, with acharge of gas oil, may be assumed to be ()o F.

t this point, We commence feeding a mixture of oil and aluminum chloridehydrocarbons to the still through pipe 28. I* or large scale operation a plurality of such pi s is desirable for complete absorption of the chloride and efficient reaction. This feeding of aluminum chloride sets up a vigorous reaction in the still and produces an evolution of vapors which are condensed in condenser #34. The gravity of the distillate evolved is tested and if it is toolight, the pressure is cautiously and slightly decreased. If it is too heavy, the pressure is conversely increased.

. At this point, we commence feeding in an additional quantity of hydrocarbon oil in amounts such that the totalfeed will substantially compensate for the loss as distil` late, together with the calculated loss of oil which Iis converted into stable sludge compounds and the amount lost as permanent gases. If the precise amount has notl been previously determined oil ma be fed in at substantially the rate the distillate is evolved plus 2 or 3 per cent. Repeated tests are made on the distillate and the necessary pres- -sure corrections are correspondingly made.

During the first few hours of ope-ration, a

gradual change in pressure or temperature is necessary to hold the evolved distillate constant in composition, which is desirable. Petroleum oils consist of a number of different components of varying response to the catalytic activity of aluminum chloride. By the procedure just described, we cause those components which react with .least avidity to accumulate in the still until they have. 1n-

creased in proportion, while those which,

react with the greatest avidity decrease correspondingly.l The net .result is to build up that in any unit o time, the components exi'sting in the feed oil are decomposed in the same ratio as they are charged to the still.

During the first few hours of operation,

-in the still such a ro rtion of com/ponents this limiting condition -is being continuously approachedand at the -end of a few hours, the c arge will have come to ,a definite equilibrium andwill not thereafter change in com. position. From this point on, the variousV components existing in the oil fed to the still As soon as distillate bewill be decomposed in the ratio in which they I tenaces Arespectively exist in the feed, with the production of a substantially uniform and unchanging composition of evolved distillate. Under these conditions, it is qulte feasible to take off or 40 per cent per hour` o f the quantity of liquid in the still as dlstillate Without undue mechanical vtransport ofA charge or loss 'of aluminum chloride. The rate at which distillate is evolved is a d1- rect function of the rate at which the catalyst is supplied and subject to the limitation just expressed, may be controlled thereby. The particular rate of running mentioned will of course be understood as illustrative merely and not in any sense in limitation of `that which maybe practically maintained without departing from the process.

After operating in this manner for a considerable period, depending of course on the rate maintained,'the amount of sludge which has accumulated in the still will be too great for the most economical operation, and at this point, the burner is shut oil", the feeds are stopped and by proper mani ulation' of valves 26 and 21, a quantity of t e sludge is withdrawn. It is desirable to keep the stirrer moving during this stage of 'the operation. As soon as this withdrawal has been accomplished, the burner is again turned on and the feed of oil and alumlnum chloride is resumed. Distillation will roceed as before.

` It is of course necessary rom time lto time to withdraw condensate from receiver 36 by means of pipe 41 and this should be done so gradually-as not to materially change the pressure.

We claim:

l. The -method of converting oils to lower boiling oil products, which comprises heating the oilto be converted to a temperature above its atmospheric pressure boiling point and between 650 and 750 F., in the presence of active aluminum chloride, distilling the oil while maintaining pressure thereupon greater than its vapor ressure and less than the vapor pressure o the lrelatively light constituents at that temperature, and withdrawing vapors predominantly composed of the light constituents.

2. Process according to claim 1, in which "er than its vapor pressure and less than the vapor'pressure of the relatively light constituents at that temperature, withdrawing vapors predominantly composed of the light constituents, and controlling the pressure to maintain the desired characteristics of the converted products.

4. The method of converting hydrocarbon oil into lower boilin oil products, which comprises heating sai oil under pressure between 100 and 300 lbs. per sq. in. to a temperature above its atmospheric ressure boiling point and between 650 and 50 F., adding fresh oil at a rate suicient to maintain the volume of still contents substantially constant2 adding thereto a catalyst containing alumlnum ychloride in a uniform and sustained manner, at alrate sufficient to maintain the desired rate of evolution of distillate, modifying the temperature or pressure to the extent necessar to maintain a distillateA of predominantly ght constituents, until a condition of equilibrium'is obtained, and thereafter continuing the operation under uniform conditions of temperature and pressure.

NATHANIEL E. LOOMlS. LOUIS BURGESS. 

